It depends on what you mean by mediator. Agree that organizational functions are no less important than just participation.
Alas, many people underestimate the importance and complexity of the organizational process. It seems to all that it is difficult to work and to manage is easy. And I think that the administrative and managerial staff (management) is a very important component of any business process!
Team work is one of the key bases for the project, because without folded work the projects success cannot be seen, its a fact
Before you create a project and enter the market, you always need to resolve the issue with the organization, in any team there is a leader who controls other team members.